FINERACT-802-restrict-client-to-have-single-self-service-user (#664)

fineract-provider/src/main/java/org/apache/fineract/useradministration/service/AppUserWritePlatformServiceJpaRepositoryImpl.java

@@ -347,6 +347,10 @@ public class AppUserWritePlatformServiceJpaRepositoryImpl implements AppUserWrit
                     username);
         }
 
+        if (realCause.getMessage().contains("'unique_self_client'")) {
+            throw new PlatformDataIntegrityException("error.msg.user.self.service.user.already.exist", "Self Service User Id is already created. Go to Admin->Users to edit or delete the self-service user.");
+        }
+
         logger.error(dve.getMessage(), dve);
         throw new PlatformDataIntegrityException("error.msg.unknown.data.integrity.issue", "Unknown data integrity issue with resource.");
     }